Semiconductor device and fabricating method thereof

ABSTRACT

A semiconductor device is provided. The semiconductor device comprises a semiconductor die having bond pads, each of which consists of a first bond pad made of a material whose ionization tendency is relatively low and a second bond pad made of a material whose ionization tendency is relatively high. The second bond pads function as sacrificial anodes to prevent the occurrence of galvanic corrosion at the interfaces between the first bond pads and conductive wires. In an embodiment, the upper surfaces of the second bond pads are marked instead of those of the first bond pads, which reduces the number of defects in the first bond pads. A method for fabricating the semiconductor device is also provided.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a semiconductor device and a method forfabricating the same.

2. Description of the Related Art

A typical semiconductor device has a structure in which conductivepatterns of a substrate are interconnected to pads of a semiconductordie attached to the upper surface of the substrate through wires.

The wires are made of gold or copper and the bond pads are made ofaluminum. The use of the different metals gives rise to a potentialdifference between the wires and the bond pads. This potentialdifference allows electrons to migrate between the wires and the bondpads. As a result, the wires having a noble potential tend to corrode ata reduced rate and the bond pads having an active potential tend tocorrode at an accelerated rate, resulting in corrosion at the interfacesbetween the wires and the bond pads. This corrosion is called “galvaniccorrosion.”

Galvanic corrosion weakens the bonding between the conductive wires andthe semiconductor die. That is, galvanic corrosion is considered to be amajor factor that causes disconnection of the conductive wires from thesemiconductor die, resulting in operational failure or malfunction ofthe semiconductor device.

In recent years, various attempts have been made to improve theperformance of semiconductor devices. Particularly, methods have beenproposed for stacking a plurality of semiconductor dies in onesemiconductor device using film-over-wires (FOWs). According to thesemethods, however, galvanic corrosion between wires and bond pads becomesa more serious problem during heating for the solidification of theFOWs.

BRIEF SUMMARY OF THE INVENTION

A semiconductor device is provided. The semiconductor device comprises asemiconductor die having bond pads, each of which consists of a firstbond pad made of a material whose ionization tendency is relatively lowand a second bond pad made of a material whose ionization tendency isrelatively high. The second bond pads function as sacrificial anodes toprevent the occurrence of galvanic corrosion at the interfaces betweenthe first bond pads and conductive wires. In an embodiment, the uppersurfaces of the second bond pads are marked instead of those of thefirst bond pads, which reduces the number of defects in the first bondpads. A method for fabricating the semiconductor device is alsoprovided.

The present invention will be more apparent from the following detaileddescription taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a cross-sectional view illustrating a semiconductor deviceaccording to an embodiment of the present invention;

FIG. 1B is an enlarged view illustrating area 1B of FIG. 1A;

FIG. 1C is a plan view of a semiconductor die used in the semiconductordevice according to the embodiment of the present invention;

FIG. 2A is a cross-sectional view illustrating a semiconductor deviceaccording to a further embodiment of the present invention;

FIG. 2B is an enlarged view illustrating area 2B of FIG. 2A;

FIG. 3A is a cross-sectional view illustrating a semiconductor deviceaccording to another embodiment of the present invention;

FIG. 3B is an enlarged view illustrating area 3B of FIG. 3A;

FIG. 4 is a cross-sectional view illustrating a semiconductor deviceaccording to another embodiment of the present invention;

FIG. 5 is a flow chart for explaining a method for fabricating asemiconductor device according to an embodiment of the presentinvention; and

FIGS. 6A, 6B, 6C, 6D, 6E, 6F are cross-sectional views for explaining amethod for fabricating a semiconductor device according to an embodimentof the present invention.

Common reference numerals are used throughout the drawings and thedetailed description to indicate the same elements.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1A, there is illustrated a cross-sectional view of asemiconductor device 100 according to an embodiment of the presentinvention. Referring to FIG. 1B, there is illustrated an enlarged viewof area 1B of FIG. 1A. Referring to FIG. 1C, there is illustrated a planview of a semiconductor die 130 used in the semiconductor device 100according to the embodiment of the present invention.

As illustrated in FIGS. 1A through 1C, the semiconductor die 100comprises a substrate 110, a semiconductor die 130 attached to the uppersurface of the substrate 110, conductive wires 140 electricallyconnecting the substrate 110 to the semiconductor die 130, and anencapsulant 150 formed surrounding the semiconductor die 130. Thesemiconductor device 100 may further comprise solder balls 160 formedunder the substrate 110.

The substrate 110 provides a base for the fabrication of thesemiconductor device 110. The substrate 110 includes an insulating layer111, lands 112 formed on the lower surface of the insulating layer 111,conductive vias 113 penetrating the insulating layer 111 and connectedto the respective lands 112, conductive patterns 114 formed on the uppersurface of the insulating layer 111 to be connected to the respectiveconductive vias 113, and a solder mask 115 covering an area other thanareas where the lands 112 are formed.

The insulating layer 111 is substantially in the form of a thin plateand plays a basic role in insulating the overlying semiconductor die 130from an external circuit. To this end, the insulating layer 111 isformed of an electrically insulating material such as a thermosettingresin or a polymer (e.g., polyimide).

The lands 112 are formed on the lower surface of the insulating layer111. Only one land 112 may be provided. In the case of a land grid array(LGA) type, the lands 112 are directly electrically connected to anexternal circuit. In the case of a ball grid array (BGA) type, the lands112 are electrically connected to an external circuit through solderballs 160. To this end, the lands 112 are made of highly electricallyconductive copper or its equivalent.

The conductive vias 113 are formed so as to penetrate the insulatinglayer 111 in relation to the respective lands 112. The conductive vias113 electrically connect the lands 112 and the respective conductivepatterns 114. The conductive vias 113 may be formed by filling via-holeswith a metal when the conductive patterns 114 are formed. The conductivevias 113 are made of highly electrically conductive copper or itsequivalent.

The conductive patterns 114 are formed on the upper surface of theinsulating layer 111. The conductive patterns 114 are electricallyconnected to the semiconductor die 130. The conductive patterns 114 areelectrically connected to an external circuit through the conductivevias 113 and the lands 112. The conductive patterns 114 are made ofhighly electrically conductive copper or its equivalent.

The solder mask 115 is formed on the lower surface of the insulatinglayer 111. The solder mask 115 is formed so as to cover an area otherthan areas where the lands 112 are exposed. The solder mask 115 isformed of a highly insulating material selected from benzocyclobutene(BCB) resins, polyimide and equivalents thereof.

The semiconductor die 130 is attached to the upper surface of thesubstrate 110 by means of an adhesive 120. The adhesive is a highlyviscous material (such as an epoxy resin or an adhesive tape) or itsequivalent.

The semiconductor die 130 is an integrated circuit made ofsingle-crystal silicon, polycrystalline silicon, amorphous silicon or anequivalent thereof as a main material using a semiconductormanufacturing process.

The semiconductor die 130 includes one or more bond pads 131 (131 a; 131b) on the upper surface thereof. The bond pads 131 provide passagesthrough which the semiconductor die 130 electrically inputs/outputssignals from/to the outside.

Each of the bond pads 131 is divided into the first bond pad 131 a andthe second bond pad 131 b. First bond pad 131 a is sometimes called aprotected or cathodic bond pad 131 a. Second bond pad 131 b is sometimescalled a sacrificial or anodic bond pad 131 b. The first bond pads 131 acontact and are electrically connected to the respective second bondpads 131 b.

The first bond pad 131 a is positioned outwardly relative to the secondbond pad 131 b in the region of the bond pad 131. The first bond pad 131a is bonded to the corresponding conductive wire 140 and is connected tothe corresponding conductive pattern 114 of the substrate 110 throughthe conductive wire 140. Accordingly, the outward positioning of thefirst bond pads 131 a with respect to a plane parallel to the uppersurface of the semiconductor die 130, sometimes called the plane of thesemiconductor die 130, leads to a reduction in the length of theconductive wires 140, thus contributing to the reduction of electricalnoise signals. The first bond pads 131 a can be made of aluminum.

Each of the second bond pads 131 b is positioned more inwardly than andin lateral contact with the corresponding first bond pad 131 a. Thesecond bond pads 131 b prevent the occurrence of galvanic corrosion inthe first bond pads 131 a. To this end, the second bond pads 131 b aremade of a metal having a higher ionization tendency than a metal for thefirst bond pads 131 a, so that the second bond pads 131 b can be morereadily oxidized than the first bond pads 131 a. That is, the secondbond pads 131 b function as sacrificial anodes and are corroded at ahigher rate than the first bond pads 131 a. The second bond pads aremade of a material selected from magnesium, magnesium alloys, zinc, zincalloys, cadmium, beryllium, and combinations thereof. Theoxidation/corrosion mechanism of the bond pads 131 prevents theoccurrence of galvanic corrosion at the interfaces between the firstbond pads 131 a and the conductive wires 140 after bonding.

In a test for the integrity of the wire bonding using a probe, thesecond bond pads 131 b may be marked instead of the first bond pads 131b, which ensures firm bonding between the conductive wires 140 and thefirst bond pads 131 a.

Although not particularly shown in the drawings, there is no need tobond the second bond pads 131 b to the first bond pads 131 a in aone-to-one relationship. Namely, one or more second bond pads 131 b maybe bonded to each of the first bond pads 131 a. Stated another way, thebond pads 131 include the first bond pads 131 a and at least one secondbond pad 131 b electrically connected to the first bond pads 131 a. Inthis case, there is no restriction on the position of the second bondpads 131 b on the upper surface of the semiconductor die 130. Thisirregular configuration of the bond pads 131 is disadvantageous in termsof anticorrosive effects but allows the formation of the second bondpads 131 b in a simple manner, which enables the fabrication of thesemiconductor device 100 at reduced cost, when compared to theconfiguration of the first and second bond pads 131 a and 131 b in aone-to-one relationship.

The conductive wires 140 electrically connect the substrate 110 and thesemiconductor die 130. Specifically, the conductive wires 140electrically connect the conductive patterns 114 of the substrate 110and the first bond pads 131 a of the semiconductor die 130. Theconductive wires 140 may be made of a highly conductive material, suchas gold, silver or copper.

According to the prior art, the use of conductive wires made of gold orcopper, which is a nobler metal than aluminum, causes galvanic corrosionin aluminum-made bond pads.

In contrast, the use of the second bond pads 131 b made of a materialhaving a higher ionization tendency than a material for the first bondpads 131 a in the semiconductor device 100 according to the embodimentof the present invention prevents the occurrence of galvanic corrosionin the bond pads 131 of the semiconductor die 130.

The encapsulant 150 is formed surrounding the semiconductor die 130 andthe conductive wires 140 on the substrate 110. The encapsulant 150protects the elements from the ambient environment. The encapsulant 150is formed using a material selected from epoxy resins, silicone resinsand equivalents thereof that are widely used in the art.

The solder balls 160 have a substantially spherical shape and areconnected to the lower surface of the substrate 110. In a ball gridarray (BGA) structure, the solder balls 160 electrically connect thelands 112 of the substrate 110 and an external circuit. The solder balls160 are easy to produce and handle and are made of a material selectedfrom tin, lead, silver, silver alloys and combinations thereof, all ofwhich have melting points.

As described above, in the semiconductor device 100 according to theembodiment of the present invention, each of the bond pads 131 of thesemiconductor die 130 consists of the first bond pad 131 a made of amaterial whose ionization tendency is relatively low and the second bondpad 131 b made of a material whose ionization tendency is relativelyhigh. Therefore, the second bond pads 131 b function as sacrificialanodes to prevent the occurrence of galvanic corrosion in the first bondpads 131 a bonded to the conductive wires 140 and to prevent damage ofthe first bond pads 131 a resulting from marking by a probe.

Hereinafter, a description will be given of the construction of asemiconductor device 200 according to a further embodiment of thepresent invention.

Referring to FIG. 2A, there is illustrated a cross-sectional view of thesemiconductor device 200. Referring to FIG. 2B, there is illustrated anenlarged view of area 2B of FIG. 2A.

As illustrated in FIGS. 2A and 2B, the semiconductor device 200comprises a substrate 110, a semiconductor die 230 attached to thesubstrate 110 by means of an adhesive 120, conductive wires 140, and anencapsulant 150. The semiconductor device 200 may further comprisesolder balls 160 formed under the substrate 110. The same referencenumerals are used to designate elements having the same structure andfunction as the elements of the previous embodiment. Differences of thesemiconductor device 200 from the semiconductor device 100 will bemainly explained below.

The semiconductor die 230 is attached to the upper surface of thesubstrate 110 by means of the adhesive 120. The semiconductor die 230includes one or more bond pads 231 (231 a; 231 b) on the upper surfacethereof. In accordance with this embodiment, each bond pad 231 includesa first bond pad 231 a and a second bond pad 231 b. First bond pad 231 ais sometimes called a protected or cathodic bond pad 231 a. Second bondpad 231 b is sometimes called a sacrificial or anodic bond pad 231 b.

The first bond pads 231 a are formed on the upper surface of thesemiconductor die 230 and are inwardly indented to a predetermined depthto form the second bond pads 231 b.

The bond pads 231 are planar in shape, which is determined as a whole bythe shape of the first bond pads 231 a. Inner portions of the first bondpads 231 a with respect to the plane of the semiconductor die 230 areetched to a predetermined depth to form etched cavities, sometimescalled etched portions, in the first bond pads 231 a. The second bondpads 231 b are formed in the respective etched cavities of the firstbond pads 231 a. The first bond pads 231 a are connected to conductivepatterns 114 of the substrate 110 through the respective conductivewires 140.

The second bond pads 231 b are filled in the etched portions of thefirst bond pads 231 a. The second bond pads 231 b are made of a materialwhose ionization tendency is higher than a material for the first bondpads 231 a. Accordingly, the second bond pads 231 b function assacrificial anodes to prevent the first bond pads 231 a from galvaniccorrosion.

As described above, in the semiconductor device 200 according to theembodiment of the present invention, the bond pads 231 are formed byetching inner portions of the first bond pads 231 a with respect to theplane of the semiconductor die 230 to a predetermined depth and formingthe second bond pads 231 b in the respective etched portions of thefirst bond pads 231 a to prevent the first bond pads 231 a from galvaniccorrosion.

Hereinafter, a description will be given of the construction of asemiconductor device 300 according to another embodiment of the presentinvention.

Referring to FIG. 3A, there is illustrated a cross-sectional view of thesemiconductor device 300. Referring to FIG. 3B, there is illustrated anenlarged view of area 3B of FIG. 3A.

As illustrated in FIGS. 3A and 3B, the semiconductor device 300comprises a substrate 110, a semiconductor die 330 attached to thesubstrate 110 by means of an adhesive 120, conductive wires 140, and anencapsulant 150. The semiconductor device 300 may further comprisesolder balls 160 formed under the substrate 110. The same referencenumerals are used to designate elements having the same structure andfunction as the elements of the previous embodiments. Differences of thesemiconductor device 300 and the semiconductor devices 100 and 200 willbe mainly explained below.

The semiconductor die 330 is attached to the upper surface of thesubstrate 110 by means the adhesive 120. The semiconductor die 330includes one or more bond pads 331 (331 a; 331 b) on the upper surfacethereof. In accordance with this embodiment, each bond pad 331 includesa first bond pad 331 a and a second bond pad 331 b. First bond pad 331 ais sometimes called a protected or cathodic bond pad 331 a. Second bondpad 331 b is sometimes called a sacrificial or anodic bond pad 331 b.

The first bond pads 331 a are formed on the upper surface of thesemiconductor die 330. The bond pads 331 are substantially planar inshape, which is determined as a whole by the shape of the first bondpads 331 a. A portion of the upper surface of each of the first bondpads 331 a is covered with the corresponding second bond pad 331 b. Thefirst bond pads 331 a are connected to conductive patterns 114 of thesubstrate 110 through the respective conductive wires 140.

Each of the second bond pads 331 b is formed on a portion of the uppersurface of the first bond pad 331 a. The second bond pad 331 b protrudesfrom the inner portion of the first bond pad 331 a with respect to theplane of the semiconductor die 330. The second bond pads 331 b are madeof a material having a higher ionization tendency than a material forthe first bond pads 331 a to prevent the first bond pads 331 a fromgalvanic corrosion. Further, the second bond pads 331 b are formed in aneasy manner on the upper surfaces of the first bond pads 331 a withoutthe need for additional etching, which enables the fabrication of thesemiconductor device 300 at reduced cost.

As described above, in the semiconductor device 300 according to theembodiment of the present invention, the first bond pads 331 a are madeof a material whose ionization tendency is relatively low and the secondbond pads 331 b are made of a material whose ionization tendency isrelatively high. Therefore, the second bond pads 331 b can be formed byrelatively simple processing to prevent the first bond pads 331 a bondedto the conductive wires 140 from galvanic corrosion.

Hereinafter, a description will be given of the construction of asemiconductor device 400 according to another embodiment of the presentinvention.

Referring to FIG. 4, there is illustrated a cross-sectional view of thesemiconductor device 400.

As illustrated in FIG. 4, the semiconductor device 400 comprises asubstrate 110, a semiconductor die 130 attached to the substrate 110 bymeans of an adhesive 120, conductive wires 140, a film-over-wire (FOW)420 formed on the semiconductor die, another semiconductor die 430stacked on the FOW 420, conductive wires 440 connecting thesemiconductor die 430 to the substrate 110, and an encapsulant 150. Thesemiconductor device 400 may further comprise solder balls 160 formedunder the substrate 110. The same reference numerals are used todesignate elements having the same structure and function as theelements of the previous embodiments. Differences of the semiconductordevice 400 from the semiconductor devices 100, 200 and 300 will bemainly explained below.

The FOW 420 is formed so as to surround wire loops of the conductivewires 140 connected to the semiconductor die 130. The FOW 420 can beformed of a general epoxy resin.

The FOW 420 has a uniform thickness and the semiconductor die 430 isstacked thereon. The FOW 420 may surround portions of the conductivewires 140 before being solidified. Alternatively, the FOW 420 may beattached to the lower surface of the semiconductor die 430, bonded toupper portions of the conductive wires 140, and solidified.

The FOW 420 is solidified by heating. However, heating may increase therisk of galvanic corrosion at the interfaces between the first bond pads131 a and the conductive wires 140. This risk can be avoided by formingsecond bond pads 131 b in lateral contact with the first bond pads 131 ausing a material having a higher ionization tendency than a material forthe first bond pads 131 a to function as sacrificial anodes.Accordingly, corrosion occurs in the second bond pads 131 b rather thanin the first bond pads 131 a. That is, the second bond pads 131 bprevent the occurrence of corrosion at the interfaces between the firstbond pads 131 a and the conductive wires 140, which makes the bondingbetween the first bond pads 131 a and the conductive wires 140 stronger.

The semiconductor die 430 stacked on the FOW 420 has the sameconstitution as the semiconductor die 130. That is, the semiconductordie 430 includes bond pads 431 (431 a; 431 b) corresponding to the bondpads 131 of the semiconductor die 130. Each of the bond pads 431 isdivided into the first bond pad 431 a and the second bond pad 431 b inlateral contact with the first bond pad 431 a. The semiconductor die 430may be provided in plurality. In this case, a plurality of FOWs may alsobe used to stack the semiconductor dies 430.

The semiconductor die 130 and the semiconductor die 430 exemplify thesemiconductor die 130 of the semiconductor device 100 according to theprevious embodiment of the present invention. However, it should beunderstood that the semiconductor die 130 and the semiconductor die 430can be independently selected from the semiconductor dies 130, 230 and330 of the semiconductor devices 100, 200 and 300 according to theprevious embodiments of the present invention.

The conductive wires 440 electrically connect lands 114 of the substrate110 and the first bond pads 431 a of the semiconductor die 430. Theconductive wires 440 have the same constitution as the conductive wires140.

As described above, in the semiconductor device 400 according to theembodiment of the present invention, at least one semiconductor die 430can be stacked on the FOW 420 overlying the semiconductor die 130, andthe semiconductor die 130 includes the first bond pads 131 a and thesecond bond pads 131 b. This construction can prevent the occurrence ofcorrosion at the interfaces between the first bond pads 131 a and theconductive wires 140 during heating for the solidification of the FOW420.

Although not particularly shown, according to another embodiment of thepresent invention, there is provided a semiconductor device having alead frame structure. Specifically, the semiconductor device comprises alead frame having lands exposed to the lower surface thereof and/orleads exposed to the side surfaces thereof as a substrate, asemiconductor die attached to the upper surface of the substrate andhaving bond pads on the upper surface thereof, and conductive wiresconnecting the lands and/or the leads of the substrate to the bond padsof the semiconductor die. Each of the bond pads of the semiconductor dieconsists of a first bond pad made of a material whose ionizationtendency is relatively low and a second bond pad made of a materialwhose ionization tendency is relatively high. Therefore, the second bondpads function as sacrificial anodes to prevent the occurrence ofgalvanic corrosion in the first bond pads bonded to the conductivewires.

An explanation of a method for fabricating the semiconductor device 100according to an embodiment of the present invention will be providedbelow.

Referring to FIG. 5, there is illustrated a flow chart for explainingthe method according to the embodiment of the present invention.Referring to FIGS. 6A through 6F, there are illustrated cross-sectionalviews for explaining the method according to the embodiment of thepresent invention.

As illustrated in FIG. 5, the method comprises the following operations:a formation of pad regions operation S1, a die attachment operation S2,a wire bonding operation S3 and an encapsulation operation S4. Themethod may further comprise the operation of a formation of solder ballsoperation S5 after encapsulation operation S4. The individual operationsof the method illustrated in FIG. 5 will be explained with reference toFIGS. 6A through 6F.

As illustrated in FIGS. 5, 6A and 6B, bond pads 131 (131 a; 131 b) areformed on a semiconductor die 130 in formation of pad regions operationS1. Specifically, the first bond pads 131 a are formed on thesemiconductor die 130, and then the second bond pads 131 b are formed soas to be in lateral contact with the respective first bond pads 131 a.The second bond pads 131 b are positioned more inwardly than the firstbond pads 131 a with respect to the plane of the semiconductor die 130.The second bond pads 131 b can be formed by forming a pattern using aphotoresist, plating a metal on the pattern by electroplating orelectroless plating, and removing the photoresist. The metal can beselected from magnesium, magnesium alloys, zinc, zinc alloys, cadmium,beryllium and combinations thereof.

As illustrated in FIGS. 5 and 6C, the semiconductor die 130 is attachedto the upper surface of a substrate 110 by means of an adhesive 120 indie attachment operation S2. Examples of the adhesive 120 include, butare not limited to, epoxy resins, adhesive tapes and equivalentsthereof.

As illustrated in FIGS. 5 and 6D, the substrate 110 is electricallyconnected to the semiconductor die 130 through conductive wires 140 inwire bonding operation S3. Specifically, the conductive wires 140electrically connect conductive patterns 114 of the substrate 110 andthe first bond pads 131 a of the semiconductor die 130. The conductivewires 140 can be made of a material selected from gold, silver, copperand combinations thereof. The second bond pads 131 b prevent theoccurrence of galvanic corrosion at the interfaces between theconductive wires 140 and the first bond pads 131 a.

Thereafter, the semiconductor die 130 and the conductive wires 140 aresurrounded by an encapsulant 150 in encapsulation operation S4, asillustrated in FIG. 5 and FIG. 6E. Suitable materials for theencapsulant 150 include epoxy resins, silicone resins and equivalentsthereof, but are not limited thereto.

The method may further comprise the operation of forming solder balls160 on the lower surface of the substrate 110 in solder balls operationS5, as illustrated in FIG. 5 and FIG. 6F. The solder balls 160 areelectrically connected to lands 112 of the substrate 110. The solderballs 160 can be made of a material selected from tin, lead, silver,silver alloys and combinations thereof.

As already explained, in the semiconductor device 100, the second bondpads 131 b prevent the occurrence of galvanic corrosion at theinterfaces between the first bond pads 131 a and the conductive wires140.

Although not particularly shown, in the semiconductor device 200 ofFIGS. 2A, 2B, formation of pad regions operation S1 may be carried outby forming first bond pads 231 a, etching portions of the first bondpads 231 a, and electroplating or electroless plating a metal on theetched portions to form second bond pads 231 b.

In the semiconductor device 300 of FIGS. 3A, 3B, formation of padregions operation S1 may be carried out by forming first bond pads 331 aand electroplating or electroless plating a metal on the inner uppersurfaces of the first bond pads 331 a to form second bond pads 331 b.

The subsequent operations are the same as those of the method forfabricating the semiconductor device 100.

In the semiconductor device 400 of FIG. 4, a series of operations offorming a FOW 420, attaching a semiconductor die 430 to the FOW 420 andconnecting the substrate 110 to the semiconductor die 430 throughconductive wires 440 is repeated at least one time between wire bondingoperation S3 and encapsulation operation S4.

Although not particularly shown, the semiconductor device having a leadframe structure can be fabricated by preparing a lead frame as thesubstrate and carrying out operations S1 through S4.

This disclosure provides exemplary embodiments of the present invention.The scope of the present invention is not limited by these exemplaryembodiments. Numerous variations, whether explicitly provided for by thespecification or implied by the specification or not, such as variationsin structure, dimension, type of material and manufacturing process, maybe implemented by one skilled in the art in view of this disclosure.

1. A semiconductor device, comprising: a substrate comprising aconductive pattern; a semiconductor die attached to an upper surface ofthe substrate, the semiconductor die comprising a bond pad on an uppersurface of the semiconductor die, the bond pad comprising a protectedbond pad and a sacrificial bond pad electrically connected to theprotected bond pad, wherein the protected bond pad and the sacrificialbond pad are made of different metals; a conductive wire electricallyconnecting the conductive pattern to the bond pad; and an encapsulantencapsulating the semiconductor die and the conductive wire.
 2. Thesemiconductor device of claim 1, wherein the sacrificial bond padcomprises a material selected from the group consisting of magnesium,magnesium alloys, zinc, zinc alloys, cadmium, beryllium, andcombinations thereof.
 3. The semiconductor device of claim 1, whereinthe protected bond pad comprises aluminum.
 4. The semiconductor deviceof claim 1, wherein the metal of the protected bond pad has anionization tendency lower than an ionization tendency of the metal ofthe sacrificial bond pad.
 5. The semiconductor device of claim 1,further comprising a plurality of bond pads comprising protected bondpads, wherein one or more sacrificial bond pads are electricallyconnected to the protected bond pads.
 6. The semiconductor device ofclaim 1, wherein the bond pad is divided into the protected bond pad andthe sacrificial bond pad.
 7. The semiconductor device of claim 1,wherein the protected bond pad is positioned outwardly relative to thesacrificial bond pad with respect to a plane parallel to the uppersurface of the semiconductor die.
 8. The semiconductor device of claim1, wherein the protected bond pad is parallel to and in lateral contactwith the sacrificial bond pad on the upper surface of the semiconductordie.
 9. A semiconductor device, comprising: a substrate comprising aconductive pattern; a semiconductor die attached to an upper surface ofthe substrate, the semiconductor die comprising a bond pad on an uppersurface of the semiconductor die, the bond pad comprising a protectedbond pad and a sacrificial bond pad electrically connected to theprotected bond pad, wherein the protected bond pad comprises a cavityindented to a predetermined depth from an upper surface of the protectedbond pad, the sacrificial bond pad being formed in the cavity; aconductive wire electrically connecting the conductive pattern to thebond pad; and an encapsulant encapsulating the semiconductor die and theconductive wire.
 10. A semiconductor device, comprising: a substratecomprising a conductive pattern; a semiconductor die attached to anupper surface of the substrate, the semiconductor die comprising a bondpad on an upper surface of the semiconductor die, the bond padcomprising a protected bond pad and a sacrificial bond pad electricallyconnected to the protected bond pad, wherein the sacrificial bond padprotrudes from an upper surface of the protected bond pad; a conductivewire electrically connecting the conductive pattern to the bond pad; andan encapsulant encapsulating the semiconductor die and the conductivewire.
 11. A semiconductor device, comprising: a substrate comprising aconductive pattern; a semiconductor die attached to an upper surface ofthe substrate, the semiconductor die comprising a bond pad on an uppersurface of the semiconductor die, the bond pad comprising a protectedbond pad and a sacrificial bond pad electrically connected to theprotected bond pad; a conductive wire electrically connecting theconductive pattern to the bond pad; an encapsulant encapsulating thesemiconductor die and the conductive wire; and a film-over-wire (FOW)formed on the semiconductor die and another semiconductor die stacked onthe FOW.
 12. A semiconductor device, comprising: a substrate comprisinga conductive pattern; a semiconductor die attached to an upper surfaceof the substrate, the semiconductor die comprising bond pads on an uppersurface of the semiconductor die, the bond pads comprising protectedbond pads and at least one sacrificial bond pad electrically connectedto the protected bond pads, wherein the protected bond pads and the atleast one sacrificial bond pad are made of different metals; conductivewires electrically connecting the conductive pattern to the bond pads;and an encapsulant encapsulating the semiconductor die and theconductive wires.
 13. A method for fabricating a semiconductor devicecomprising: forming a bond pad on an upper surface of a semiconductordie, the bond pad comprising a protected bond pad and a sacrificial bondpad electrically connected to the protected bond pad, wherein theprotected bond pad and the sacrificial bond pad are made of differentmetals; attaching a lower surface of the semiconductor die to an uppersurface of a substrate; electrically connecting the protected bond padto a conductive pattern of the substrate through a conductive wire; andsurrounding the semiconductor die by an encapsulant on the upper surfaceof the substrate.
 14. The method of claim 13, wherein the sacrificialbond pad comprises a material selected from the group consisting ofmagnesium, magnesium alloys, zinc, zinc alloys, cadmium, beryllium, andcombinations thereof.
 15. The method of claim 13, wherein the protectedbond pad comprises aluminum.
 16. The method of claim 13, wherein theprotected bond pad is parallel to and in lateral contact with thesacrificial bond pad on the upper surface of the semiconductor die. 17.A method for fabricating a semiconductor device comprising: forming abond pad on an upper surface of a semiconductor die, the bond padcomprising a protected bond pad and a sacrificial bond pad electricallyconnected to the protected bond pad, wherein the protected bond padcomprises a cavity indented to a predetermined depth from an uppersurface of the protected bond pad, the sacrificial bond pad being formedin the cavity; attaching a lower surface of the semiconductor die to anupper surface of a substrate; electrically connecting the protected bondpad to a conductive pattern of the substrate through a conductive wire;and surrounding the semiconductor die by an encapsulant on the uppersurface of the substrate.
 18. A method for fabricating a semiconductordevice comprising: forming a bond pad on an upper surface of asemiconductor die, the bond pad comprising a protected bond pad and asacrificial bond pad electrically connected to the protected bond pad,wherein the sacrificial bond pad protrudes from an upper surface of theprotected bond pad; attaching a lower surface of the semiconductor dieto an upper surface of a substrate; electrically connecting theprotected bond pad to a conductive pattern of the substrate through aconductive wire; and surrounding the semiconductor die by an encapsulanton the upper surface of the substrate.